580 EX Doesn't Keep Up with 5D Mk III?

[WayneHixson]

Hello! Newbie and first time poster. I am not an experienced flash user, so wasn't sure what to expect when shooting in burst mode at a party over the weekend. I had the 580 set in ETTL and angled up to bounce off the ceiling. I had the 5D in normal burst mode (not high speed). When shooting, I ran into a situation where the flash would work for the first exposure, but the following exposures were dark. Trying it last night at home, I ran 5 burst exposures; the flash would fire for the first two but not the last three. When setting the flash in locked horizontal position (not bouncing), it worked for all 5 exposures. What would cause this behavior? Low batteries? Can the camera be set to 'wait' for the flash?

Thanks!

Wayne

[Skirball]

All flashes have a recycle time, and battery powered ones are especially slow.  If you’re shooting low-power flashes you can get multiple shots in a burst, and if there are small rests in-between bursts it may keep up with the camera without any misses.  But if you’re doing higher power flashes you may get as little as a single flash before it needs to recharge.   This is normal.  Battery type, battery charge, battery age, and flash power can all affect recycle time.  If you’re doing full power pops it can take some time in-between shots.  If you're bouncing, then you're going to be using more power.

You can reduce recycle time by using an external power pack, but this is normal behavior for a flash.  Especially with the fast burst rates cameras have these days.

[Steviewonder1]

Also down in the instruction manual it says no more than 10 full stroboscopic flashes and then let it cool down. I have an external battery pack with LION batts in it and the flash and I can do 10 full pops with 1 or so seconds between shots and sometimes less. It is easier to get multiple flashes not bouncing it off the ceiling. If you try to do too many flashes too fast, the flash will shut down for 10-15 minutes to cool the insides.

[cicopo]

I also have & use the Canon Power Pak & it really speeds up the recycle time. Some think it's overpriced but not me. It isn't just more batteries in a separate pak . It has electronics to speed up / override the standard stuff inside the flash.

[TCampbell · Accepted solution]

This is completely normal and _every_ flash has the same issue.

The batteries charge up capacitors internal to the flash.  It's those capacitors which deliver the sudden burst of power to provide the flash.  Once the flash fires, the batteries need to replenish the power in the capacitors to be ready for the next flash.  The more batteries (and the fresher and more fully charged those batteries are) the faster the flash recycles.

But there's more.

If you're shooting in E-TTL, the flash guages how much power it needs to deliver to adequately illuminate the scene.  If you're shooting in manual, you can set the fraction of power that the flash delivers (e.g. do you want a full power flash (1/1) or do you want some fraction (e.g. 1/32nd power?).  If the flash has to deliver it's "full" amount of power, then it'll take longer to recycle.  If it only delivers a fraction of it's power, it'll be ready to go again INSTANTLY (no delay) because it still has enough power in the capacitors to fire another fractional burst of power.  In fact... when shooting in "high speed sync" mode, this is precisely how the flash works... it flashes VERY rapidly but using only a tiny fraction of it's full potential for each burst.

If you need "full" power and you need it FAST there's a solution for that too.  You have to cluster flashes to work as a gang.  e.g. if I cluster 4 flashes together, then each flash would only need to fire at 1/4 power and yet as a gang they're still provided the light of "full" power.  That means after 1 burst, each light still has 3/4s of it's power left and it could fire four times in very rapid succession.  Only after the 4th flash would you have to pause while the flashes recycle.  I think you can cluster up to 15 flashes -- you'd never need that many.

For your purposes, just make sure your batteries are fresh.  (Tip:  Sanyo Eneloop rechargeable batteries are great in these flashes and save you from buying single-use batteries.)  If it's not fast enough for you even with fresh batteries, then buy the external battery pack accessory for the 580EX II (which can effectively triple the amount of power supplied to the flash.).

[WayneHixson]

Thanks everyone! Very useful information